A group of usually lethal, clinically similar paralytic syndromes have been described by Sabin. Of these only that resulting from ingestion of the fruit of Karwinskia humboldtiana is of known etiology. Preliminary studies have resulted in the isolation and partial characterization of the toxins. We propose to elucidate the structures of these materials and to synthesize the principal toxic compounds. This will provide a firm basis for studies of the detailed biological effects caused by these toxins. Such studies will provide new insights to a group of paralytic diseases little understood at present.